System for driving or braking a strip

ABSTRACT

A system to apply a strip to a roller including a shoe movable radially toward the roller in the region where the strip will engage the roller, a jack to move the shoe and means to inject a fluid between the shoe and strip to transfer the force of the jack to the strip while keeping the shoe clear of the strip.

United States Patentv 1 51 Apr. 3, 1973 Gay [54] SYSTEM FOR DRIVING ORBRAKING ASTRIP [75] Inventor: Pierre Gay, La Tour-en-Jarez,

France [73] Assignee: Creusot-Loire Enterprises, Paris,

France [22] Filed: Apr. 7, 1971 [21] Appl. No.: 131,925 1 [30] ForeignApplication Priority Data Mar. 8, 1970 France ..70I6777 July 17, 1970France ..7026343 [52] U.S. Cl .....226/95 [51]. Int. Cl. ..B65li 23 /24[58] Field of Search.....l "226/7, 95, 195,183

[56] References Cited UNITED STATES PATENTS- 2,955,732 10/1960 Stobb"226/95 2/1964 Davison ..226/95X 6/1966 Altobelli ..226/95 PrimaryExaminer-Richard A. Schacher Attarney-Cameron, Kerkam & Sutton 571ABSTRACT A system to apply a strip to a roller including a shoe movableradially toward the roller in the region where the strip will engage theroller, a jack to move the shoe and means to inject a fluid between theshoe and strip to transfer the force of the jack to the strip whilekeeping the shoe clear of the strip.

2 Claims, 2 Drawing Figures PATENTEM N 375 3,724,735

During the various stages in the production of a metal strip it isfrequently necessary for it to move continuously and for it to besubjected to appropriate traction conditions in various zones for thepurposes of the operations that it is required to undergo in such zones.

Means are therefore required to impart these different required tractionconditions to the strip.

Such means are generally either driving or braking rollers, around whichthe strip extends over an angle a, as shown in FIG. 1.

The known formulas indicate the limits in which a roller of this kindcan convert a tension t into an outlet tension t The following equationapplies:

in whichfis the coefficient of friction of the strip on the roller and ais the angle by .which the strip extends around the roller. The tensionincrease or reduction capacity is therefore limited by the slip of thestrip on the roller.

To increase this drive capacity, it is conventional practice to usepressure rollers which apply the strip against the drive or brakeroller.

These pressure rollers have a limited effect, because the force thatthey exert on the strip must not be such as to result in any deformationof the latter.

They also .have the very serious disadvantage of producing faults in thestrip guidance, and such faults may be such that the strip'leaves itsnormal path, so that itis then impossible for the production line tocontinue operating.

To increase this drive capacity, it has also been proposed to exertpressure on the strip in the region in which the said strip is appliedto the roller. In the prior art systems, a stationary member is disposedoutside the roller and formsa chamber between itself and the roller, apressure fluid being introduced into said chamber to apply the strip tothe roller.

These known systems have the disadvantage of requiring a considerableflow of pressure-transmitting fluid. There is an appreciable clearancebetween the chamber and the roller over which the strip (of varyingthickness) extends.

The object of this invention is to improve these latter known systems.

According to the present invention there is provided a system fordriving a strip comprising a roller for receiving strip, a shoeapplicable radially toward the roller in the region in which the stripwill be received, and means to inject a pressure fluid radially inwardthe shoe, the system being characterized in that the shoe is slightlymovable in a fixed frame by ajack so that when pressure fluid is appliedbetween the shoe and a strip received by theroller, the strip will beapplied against the roller with a force equal to that exerted by thejack on the shoe, while contact between the shoe and'the strip will beprevented by the formation of a very thin fluid cushion which will leaveonly a very small clearance between the shoe and the strip and whichwill prevent any rubbing of the shoe on the strip.

According to a specific feature of the invention, the

pressure fluid is compressed air.

It Wlll be apparent that the combination of the effect of the pressureof the jack on the shoe results in a very small flow of pressure fluidbetween the shoe and the strip and also prevents any rubbing of the shoeon the strip. These two considerable advantages are not found in theprior art systems. In the invention, firstly, the fluid consumption isgreatly reduced and, secondly, the disadvantages of the shoe rubbing onthe strip are eliminated.

One embodiment of the system according to the invention willbe explainedhereinafter by way of example without limiting force in order that theinvention may be more readily understood.

FIG. 1 is a diagrammatic end elevation of a roller with a strip appliedto it.

FIG. 2 is a vertical section of this embodiment.

The strip 1 moves in the direction of the arrow and passes successivelyaround a deflector roller 2, and then a drive (or brake) roller 3 andfinally a deflector roller 4. Reference 9 denotes the frame whichsupports the bearings forming the axes of rotation of the rollers 2, 3and 4.

A shoe Sis guided in the frame 9 at 10.

A jack 7 fed with pressure fluid by the device 8 applies the shoe 5against the strip 1 in the region where said strip extends around theroller 3. A device 6 feeds compressed air to the cavity of the shoe 5adjacent the strip.

A valve 11 provides a varying pressure loss between the supply 6 and theshoe 5 so that the rate of flow of the fluid can be reduced. Said flowwill be adjusted for a given force of the jack 7 to a value justsufficient to prevent the shoe 5 from rubbing on the strip.

Of course, variants and improvements as to detail, and the use ofequivalent means, are possible without departing from the scope of theinvention.

I claim:

l. A system for driving a strip comprising a roller for receiving astrip, a shoe movable radially toward the roller in the region in whichthe strip is received, and means for injecting compressed air radiallyinward of said shoe against said strip, a fixed frame movably supportingsaid shoe, a jack moving said shoe in said frame whereby when compressedair is applied between said shoe and said strip on said roller, saidstrip is applied against said roller with a force equal to that exertedby said jack on said shoe, the compressed air forming a very thin fluidcushion and providing a very small clearance between said shoe and saidstrip preventing rubbing of said shoe on said strip.

2. A system according to claim 1, said means for injecting pressurefluid between said shoe-and said strip including a valve providing anadjustable pressure loss.

a m: a a

1. A system for driving a strip comprising a roller for receiving astrip, a shoe movable radially toward the roller in the region in whichthe strip is received, and means for injecting compressed air radiallyinward of said shoe against said strip, a fixed frame movably supportingsaid shoe, a jack moving said shoe in said frame whereby when compressedair is applied between said shoe and said strip on said roller, saidstrip is applied against said roller with a force equal to that exertedby said jack on said shoe, the compressed air forming a very thin fluidcushion and providing a very small clearance between said shoe and saidstrip preventing rubbing of said shoe on said strip.
 2. A systemaccording to claim 1, said means for injecting pressure fluid betweensaid shoe and said strip including a valve providing an adjustablepressure loss.